1. Engineering World Health Began in Memphis, TN, 2001 Improves hospital conditions in developing countries Funds building of medical device prototypes Branches to chapters at schools throughout U.S. www.ewh.org

2. Abstract Gas flow meters measure the rate at which a gas is flowing. This is important in the medical field to measure how fast the patient is receiving O 2, CO 2, or medical grade air. Third World countries cannot afford current flow meters to use in their health care systems.

3. Problem Statement Design a gas flow meter with continuous or single readout that can be manufactured for less than $2 when produced in quantities of 500.

4. Background and Motivation Applicable to engineering Essential to Anesthesiologist Imperative to saving lives Important to economy Unable to afford expensive products

5. Current Products Rotameter Venturi Turbine Ultrasonic Pneumotachographs Anaesthesia U.K.

6. Design Requirements Flow source: O 2, CO 2, or medical air Range: 0-15LPM Readouts: single or continuous Dimensions: 1” x 1” x 4” or 4” x 4” x 1” Accuracy: within 10% of actual flow rate Cost: < $2 per flow meter when mass produced

7. Rotameter Concepts Area is varied to create pressure difference Design is flattened to allow for inexpensive production Plexiglas is clear and durable Bead is filled with epoxy serves as float 1” ½”

8. Rotameter Testing Tested in Dr. Chesler’s Lab Used Vaseline and beads Connected to air source Failed to raise float at proper rates

9. Venturi Concepts Obstruction creates pressure difference Water is displaced Acrylic used for body Tubing is clear and flexible Manometer Obstruction Gas In

10. Venturi Testing Pictures Venturi meter taped to fume hood on black plastic to aide reading of manometer Venturi meter in series with calibrated rotameter for testing

11. Venturi Testing Procedure Air Testing: Taped device to fume hood on black plastic Performed practice tests to eliminate human error Drew lines for 2LPM, 5LPM, 8LPM on manometer Read flow rates for 5 trials 2LPM flow did not give noticeable readings Nitrogen Testing: Rotamter not calibrated for Nitrogen 2LPM flow was noticeable but inaccurate

14. Conclusion Venturi flow meter works well and meets design requirements for a single readout meter Accuracy within 10% at more than one flow rate Rotameter is ineffective due to dimensions and high float density

15. Future Work Testing of venturi Constant flow rate of Nitrogen Higher flow rates of air Testing of rotameter Different dimensions Lower float density More secure seams

16. Acknowledgements Dr. John Webster Dr. Naomi Chesler Burke O’Neal The Machine Shop Eric Kersten References Engineering World Health. 28 April 2006. http://www.ewh.org/about/index.php Anaesthesia U.K. 30 Jan. 2006 http://www.frca.co.uk/article.aspx?articlei d=10039c0