1. Positive Displacement: The Peristaltic Pump Prepared By: -Stephanie Arbelovsky -Andrea Hektor -Christina Hynes December 17, 2004

2. Project Goals: Create a constant flow device for a point-of-use water supply system in a developing community. Develop a system that was sustainable, affordable, and readily available. Experiment with various drive mechanisms, such as a clock, pendulum, and a weight system.

3. Concept: Peristaltic Pumps Peristalsis – a natural process of involuntary wave-like successive muscular contractions by which food is moved through the digestive tract. Operates by batching a certain volume of water and forcing it along a tube. A rotor attached to an external circumference compresses and releases a flexible tube with rollers, creating a squeezing action that draws fluid through the tubing.

4. Peristaltic Pump Positive Displacement Pump (PDP) 3 Parts –Pump Head –Drive Mechanism –Tubing

5. Pump Head Masterflex® L/S Easy-load Worked only with Masterflex® tubing Torque required entirely dependent on tubing used

6. Tubing Masterflex® Precision –Nontoxic –275 degrees to -75 degrees Fahrenheit –Longer life Flow Rate Torque

7. Flow Rate SizePulsesRotationsVV/rotationRotation/ (ml) day #18180602383.9675,042 #17240802332.9136,867 #164801601440.90022,222 #14420140410.29368,293 #13777259160.062323,750

8. Torque No. ofTorque Sizeheadskg-cmoz-in #1818.6120 #1718.6120 #1613.245 #1412.940 #1311.420

9. Clocks Two Types: –Electrical –Mechanical Weights Springs Governed By Escapement Mechanism Why Not Have Gears Turn Pump Instead of Clock Hands?

10. Giving it our best shot with Tinker Toys!

11. LEGO MAN!

12. To Make It Work: –Large gears 175 teeth, medium gear 35 teeth, small gears 25 teeth –Pendulum 107.5 cm long, with escapement mechanism on last gear Period: 2.08 s –2 kg weight

13. Do-It-Yourself Kits Woodworker Kit –Templates for gears Home Assembly Kits –Can buy pre-cut clock housing –Weight/pendulum sold separately

14. Advantages Able to vary flow based on need –Can be scaled up & down Does not require constant head loss Self priming Prevents backflow Inside of tube is only area in contact with fluid –Low risk of contamination Easy & convenient maintenance and cleanup Flexible staging options – can be placed after filter

15. Disadvantages Preliminary design is expensive –Rotor, peristaltic tubing, pendulum, etc. Durability concerns if cheaper, thin walled tubing is used Availability of materials Finding a drive mechanism with enough power to turn the rotor

16. Recommendations for Further Research: Find a more practical pump head Use less expensive, flexible tubing Experiment with pendulum mechanisms in order to establish steady flow Evaluate flow rate compared to size and type of materials used

17. References and Thank Yous "Plant Extracts." [Online] Available http://www.sciences.com/scidata/edu.html February 23, 1997. “How Pendulum Clocks Work” [Online] Available http://www.howstuffworks.com November 14, 2004. “Technical Info” [Online] Available http://www.masterflex.com December 2, 2004 “Technical Info” [Online] Available http://www.barnant.com December 2, 2004 White, Frank M. Fluid Mechanics. McGraw-Hill Science/Engineering/Math; 5 th edition December 2002. Young, Donald F. ; Munson, Bruce R.; and Okiishi, Theodore H. A Brief Introduction to Fluid Mechanics, 2 nd Edition. John Wiley & Sons. October 2000. CEE 454 website and class notes Available http://ceeserver.cee.cornell.edu/mw24/cee454/ www.clockplans.com www.murrayclock.com http://www.ericharshbarger.org/lego/clock.html (A heart-felt thank you goes out to Lego Man for providing inspiration.