Yesterday I started playing around with a solid state viscometer. This viscometer differs from other more physical methods in that it simply vibrates to determine viscosity. What I did was the following
- Cut a strip of aluminum sheet.
- Place a piezo tweeter element on each side
- Tried to solder the elements to aluminum
- Soldered two Teflon coated wires to the piezo material
- Took the whole thing and cast it into epoxy as to seal it and make it rigid between the tow piezo elements.
- Ground most of the excess epoxy off after curing.
- hooked a function generator, sine wave, to one side of the unit.
- Put the oscilloscope on the other side
- Found the most resonant frequency, which in air, is about 62.5Khz
- Tried ‘er out!
So far, it seems to provide useful results. I’ve tested it with water and oil. Oil tends to dampen the signal more than water which is a good sign since oil is more viscous but less dense, thus iy’s not functioning (entirely) as a densometer.
Here are the energy differences between water and air, the blue line is the sensor value.
Well, there we have it, a prototype vibratory viscometer. I guess the next step will be to do these three things.
- Produce a variable frequency.
- Amplify and use the signal appropriately.
- Produce a useful number.
Hopefully I’m up to the challenge. 🙂