An integrated sensor system for monitoring washing processes

0,95
MB

239
stron

5090
ID Universiteit Twente

1999
rok

Contents

1. Introduction 1

1.1 Motivation . 1

1.2 Trends in sensor design. 2

1.3 General sensor concepts 4

1.4 Levels of integration 8

1.5 Outline of this thesis 11

1.6 References 12

2. Specification of the washing environment. 15

2.1 Washing. 15

2.2 Detergents 19

2.3 Sequential dosing and interfacing . 23

2.4 Conclusion and selection of washing parameters. 25

2.5 References 28

3. Selection of sensor materials based on a literature overview. 29

3.1 Introduction 29

3.2 Sensor classification by measured washing parameter 31

3.3 Sensor classification as electronic devices 43

3.4 Sensor classification by materials and technology 50

3.5 Conclusions . 67

3.6 References 71

4. A multi-purpose sensor-actuator structure . 75

4.1 Device modelling and design. 75

4.2 Experimental . 88

4.3 Conclusions . 100

4.4 References 102

4.A Hoya® glass wafer SD-1 and SD-2 datasheet 103

4.B The fabrication process . 104

5. Amperometric bleach detection 105

5.1 General concepts 105

5.2 The chemistry of hydrogen peroxide 106

5.3 Controlled potential measurement techniques 112

5.4 Experimental . 117

5.5 Summary . 124

5.6 References 125

6. Thermoresistive heating. 127

6.1 Heating a finite volume. 127

6.2 Heating an infinite volume. 129

6.3 The substrate material . 136

6.4 Mass flow measurement . 144

6.5 Summary . 146

6.6 References 147

7. Stimulus-response measurements 149

7.1 Mathematical generalisation of differential measurement systems . 149

7.2 Some examples based on available actuators. 155

7.3 Conclusions . 167

7.4 References 169

8. Ion concentration estimation using conductivity and temperature. 171

8.1 The effect of temperature on conductivity . 171

8.2 A linear minimum mean square estimation. 176

8.3 Experimental . 187

8.4 Conclusions . 193

8.5 References 195

9. Supplementary results 197

9.1 Hardness and conductivity of tap water 197

9.2 A conductivity cell on a PCB 199

9.3 Integrated conductivity sensor - temperature actuator 201

9.4 References 206

10. Concluding remarks and suggestions for further research . 207

10.1 Concluding remarks 207

10.2 Suggestions for further research 211

10.3 References 216

List of publications 217

Summary. 219