18.10.2017 | MULTIPHASE 2017 | Sebastian Schreier 1

Sebastian Schreier & Christian Poelma

Faculty 3mE, Depts. M&TT & P&E

Pressure Sensor Clusters

On the Way to 100 Pressure

Sensors on a 1-Euro Coin

18.10.2017 | MULTIPHASE 2017 | Sebastian Schreier 2

Spatial Distribution of Sloshing Pressures

• Example impacts at 80 % filling level

• Tank width 200 mm

• Sensor spacing 14.8 mm

wide

0.00 s0.02 s0.04 s0.06 s0.08 s0.10 s0.12 s0.14 s0.16 s0.18 s

14 ms

Wide configuration

Localized

impact

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What did we miss?

18.10.2017 | MULTIPHASE 2017 | Sebastian Schreier 3

Idea: Very Small Pressure Sensors

• Tank width 200 mm

• > 100 pressure sensors per line?!

• Sensor spacing < 2 mm

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18.10.2017 | MULTIPHASE 2017 | Sebastian Schreier 4

1.65

1.5

0

EPCOS Pressure Sensor C32 Industrial

• Dimensions: 1.65 x 1.65 x 1.5 mm3

• Absolute pressure sensor

• Vacuum reference cavity

• Suitable for wet (non-aggressive) media

• Measurement range 0..1.6 bar (10 bar)

• Distributed Wheatstone bridge

• Sensitivity (typ.) 22 mV/V @ 1.6 bar

• Non-linearity (typ.) 0.2%

• Operating temperature -20..85 deg C

short time (< 15 min): 105 deg C

18.10.2017 | MULTIPHASE 2017 | Sebastian Schreier 5

Engineering Considerations

• Air in cavity considered as bubble in water

• Oscillation frequency 6.6 kHz (isothermal), 7.8 kHz (adiabatic)

• Pressure drop in channel due to surface tension

• Water/air σ=0.072 N/m 700 Pa

• Cavity filled with water

• Time for shock wave to run from opening to membrane and

back: 1.5 µs 670 kHz

Conclusion: Cavity to be filled with water

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Get Going

• Step 1 get one to work (!)

5 mm

5 m

m

1st connected

sensor 19.06.2017

18.10.2017 | MULTIPHASE 2017 | Sebastian Schreier 7

Get Going

• Step 1 get one to work (!)

• Step 2 cluster many sensors

Current sensor d = 11 mm

24 new sensors

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Challenges

• Micro-electronics world

Gluing sensors to circuit board

Electric connections by wire bonding

Water proofing of assembly

High conductor density on circuit board

• Overcoming/using surface tension

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Current Status

• 1st sensors are glued and bonded (16.10.2017)

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Next steps

• Testing and evaluation of sensors in air

• 1st static testing

• 2nd dynamic behaviour

• Try applicability in water

• Testing and evaluation in water

• Proceed to sensor clusters

18.10.2017 | MULTIPHASE 2017 | Sebastian Schreier 11

(Almost) 100 Sensors on a 1-EUR Coin

46

15

13

11

7

5

9

11

13

14

15

15

82

ø23

.25

18.10.2017 | MULTIPHASE 2017 | Sebastian Schreier 12

Acknowledgments

• Thanks to our colleagues at TU Delft

• Henk van Zeijl, EWI/EKL for gluing and wire bonding

• Frits Sterk, 3mE/SHS for electronics support

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Thank You for Your Attention!

• What are your ideas for applications?

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