Prepared by: Kimball Merrill kimballme@ccu

1. ECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Topic: Dissolved Oxygen Sensors Prepared by: Kimball Merrill kimballme@cc.usu.edu 3/11/2005

2. Outline • Reference list • To explore further • Major applications • Main components • How it works • Major specifications • Limitations • Pricing • Where to buy ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

3. Reference List • Google.com • Globalspec.com • www.stevenswater.com • www.quantumanalytical.com/pdf/ATIq25d.pdf • www.mt.com • www.thermo.com • electrodesdirect.com • apcs.net ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

4. To Explore Further (Survival Pointers of Web References Etc) • Globalspec.com requires user name and password that can be easily acquired. • All quotes for pricing requested through Globalspec.com ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

5. Major Applications • Wastewater treatment • Wine production • Bio-reactions such as aquaculture and environmental testing • Ground water monitoring • Surface water monitoring ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

6. Main Components • Thin organic membrane • Two or three metal electrodes • Thermistor thermometer • An electrolyte Solution • Outer shaft housing ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

7. Example Diagrams electrodesdirect.com ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

8. Membrane Specifications • Made of FEP ( fluorinated ethylene propylene) • Usually replaceable • Approximately 50 um ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

9. Electrode Material Choices • Gold cathode, silver anode, silver/silver bromide • Lead anode and a gold cathode ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

10. How It Works • Liquid goes into the sensor. • Oxygen diffuses through the membrane. • As oxygen gets diffused the electrolyte has higher pressure which raises the current through it. • Current is measured. • Converts the measurement of the current into units of concentration. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

11. How It Works (Cont) • Generates a signal that is proportional to the present amount of oxygen. • Can determine the quantity of dissolved oxygen as a percent saturation or simply as an amount. • Generally the medium is water but can be other liquids. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

12. Two Types • Galvanic • Polarographic ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

13. Galvanic • No external voltage required. • More stable and accurate at lower levels of dissolved oxygen. • Lower maintenance cost since the components can go several months without needing replacement. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

14. Polarographic • External voltage required. • Higher maintenance cost since the components must recharged after every few weeks of being used heavily. • Two types: Ross or Clark. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

15. Major Specifications • Oxygen range • Accuracy • Response time • Minimum flow rate • Operating temperature range • Operating pressure range ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

16. Accuracy • No zero point error • Very accurate normally better than +/- 0.2mg/L ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

17. 10 seconds 15 – 20 seconds 60 seconds 90% 95% 100% Average Response Times ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

18. Mounting Options • Hand held or portable • Flow Thru (Pipeline) • In-Line (Insertion) • Convertible • Other ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

19. Locations for Possible Use • On the edge of a body of water like a lake or a river • The edge of a boat • In a stilling well away from the main flow of the water • Mounted inside a drainage pipe • On the wall of a dam • Anchored to bottom of a body of water ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

20. Limitations • Certain temperatures or pressures • Flow rate of liquid too high • Maximum distance from the medium to be measured • Amount of dissolved oxygen too high or too low to be sensed. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

21. Optional Features • Disposable membrane cap • Temperature sensor built in • Compensation of temperature • Extension attachments • LCD display module ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

22. Cleaning and Maintenance • Does not need to be cleaned if there is only a little grime • Easily cleaned using soap and water • Calibration should be done every three to six months • Replacement membranes are usually available ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

23. Where to Buy • Extech Instruments Corp • Campbell Scientific, Inc. • Honeywell Sensing and Control • Situ, Inc. • Mettler-Toledo Thornton Inc. • Ocean Optics, Inc. • Thermo Electron, Water Analysis/Orion Products • Electro-Chemical Devices, Inc ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

24. Cost Information • $199 for glass body at Electrodes Direct • $399 for Heavy Duty version at Extech Instruments Corp • $667 for flow through mounted version at Electrodes Direct • $982 for stainless steel type at Electrodes Direct ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators