Hi,
Measuring Viscosity is a very involved process, and involves precision construction to provide a stable and repetitive result.
You should be looking for a Viscosity Instrument (it probably will be a complete instrument) to suit your needs with RS232, analog, I2C or SPI output.
Keep in mind: an Arduino can not measure much, really. It can measure time and measure analog voltage levels. That's about it.
If you want to use it to measure viscosity, the key is the sensor. Find a sensor that can read the viscosity in the range you want, and offers some form of electronic signal. Usually an Arduino will be able to read that signal.
TomGeorge:
Hi,
Measuring Viscosity is a very involved process, and involves precision construction to provide a stable and repetitive result.
You should be looking for a Viscosity Instrument (it probably will be a complete instrument) to suit your needs with RS232, analog, I2C or SPI output.
What chemicals are you going to measure?
Tom....
Is there any instrument readily available in the market?
Chemical ==> Mixer of phosphoric acid (H3PO4) and sulfuric acid (H2SO4)
No matter what sensor you pick/try, there is the problem of calibration.
If I was going to design one, I would use a paddle suitable for the liquid you are dealing with. I would split the shaft between a DC electric motor and the paddle and add a magnetic coupling that could slip if the torque became too great.
then I would use an Arduino to measure the RPM of each shaft and based on the difference in RPM and after calibration, compute the relative viscosity.
Paul_KD7HB:
No matter what sensor you pick/try, there is the problem of calibration.
If I was going to design one, I would use a paddle suitable for the liquid you are dealing with. I would split the shaft between a DC electric motor and the paddle and add a magnetic coupling that could slip if the torque became too great.
then I would use an Arduino to measure the RPM of each shaft and based on the difference in RPM and after calibration, compute the relative viscosity.
Paul
Dear Paul,
Thanks a lot for your reply. Can I get any diagram kind of? It easy to understand for me.
Many years ago I've been working with various kinds of viscosity meters. Those no doubt were bought commercially by the university. No doubt nowadays they have different communication options for a computer (or Arduino, if you prefer) to read the viscosity reading from the viscometer. Those were based on a cylinder rotating in the liquid, then calculating the viscosity based on the torque.
That's the way to go if all you want to achieve with this project is a reading of the viscosity of your material. The test cylinder will have to be made of a highly chemical resistant material for use with your acids, of course. Ask the manufacturer for suggestions.
Now if you're interested in the ins and outs of measuring viscosity, you may go the complete DIY route and start with a spindle, motor, torque sensor, etc. Based on your messages I don't have the feeling that this is what you're after.
Thanks for your reply. Some plastic-like acrylic will resist my chemical. I may use this plastic to make a cylinder.
is it OK?
Better to do DIY. Because my requirements are very specific. So I may not get readily available. I am looking for someone to guide me to do this project.
Did you even do a serious search for off the shelf viscometers?
I'd be surprised if you can not change the spindle of most such devices (we could change them for different diameters which is needed for different ranges of viscosity: larger diameter for lower viscosities). Those were made from stainless steel I think. No reason it can't be done from acrylic or so, the material of the spindle doesn't matter as long as it's physically strong and stiff enough.
If you really want to go the DIY route, you'll have to study how the commercially available things work exactly. I only know the basic principles, that's enough to work with them, developing a sensor from scratch is a whole different ballgame and is going to take you months of hard work: testing, calibrating, redesigning, more testing, etc.
I recommend you to start by contacting your local university's chemistry or chemical technology department, ask if they have any courses on rheometry that you can join. That will give you the basis to understand what is going on in your viscosity meter, a basis you need to understand what you are actually measuring, and how to translate a measurement in your specific compound to a viscosity number.
That failing, contact your local representative of Mettler or a similar company specialised in measurements. Maybe you can hire an expert there that can guide you through the ins and outs of the design of such a sensor.
Here you won't find anyone to guide you building the viscometer. I happen to have a background in chemical technology and some hands on experience with using those devices, albeit well over 20 years ago by now (I'm starting to feel old at times). That's it.
Now if you have built your device, and selected a suitable sensor, and know how to turn the sensor's output into a viscosity number, then we can definitely guide you on how to read that sensor with an Arduino, and how to display the result of your calculations on a display or pass it on to a PC or so. We may even be able to help you turn your formulas into computer code.