sensor to detect oil in water

[zeeekay]

Hi,
I am working on a project to separate oil from water. My idea is to transport mixture to a transparent plastic case through pipes and then carry conduction and optical tests. Depending on the tests, the fluid will be transported to two separate containers. I need to ask , if someone has ever used IR sensors to detect colour of liquid through transparent plastic case. As I cannot plant my IR sensors inside, will planting them outside work? What is the most suitable solution for optical detection.

Thanks.

 

[keith1200rs]

I am not sure if is a help or hindrance but IR is absorbed by water. If you want to measure refractive index of water then you might need to consider short, visible wavelengths.

Keith

 

[jpanhalt]

Near infrared (NIR) might work as water is relatively clear in that region compared to its absorptions at longer wavelengths.

This Wikipedia article shows the absorption of water across a wide part of the spectrum. Note that in the NIR, water can be relatively transparent at common NIR wavelengths.

Here is an interesting and high-level article on using near infrared (NIR) to quantitate such things as oils and water.

Finally, here is a chart showing the assignments in the NIR.



So, the simple answer is yes. People have used infrared to quantitate oils and water. You will need to define the materials used for the optical cell to be sure they are compatible with both liquids and transmit the IR wavelengths you will be using.

John

 

[zeeekay]

thanks for your quick and detailed replies....I will try both near infra red and visible light solutions and will surely reply with my experiment results.
Thanks again.