# Detecting Bubbles in Nitrogen Tetroxide



## cevers (Nov 12, 2013)

Hi,

I need to be able to detect the presence of bubbles in NTO through a CANTY sightglass with a window diameter of 1.13". In order to do this I need a powerful light placed in the rear window projecting forward. The light source needs to be between 1.13" and 2.5" in diameter so the light does not blind the viewer. We tried using LED light strips to light up the fluid, but the fluid is so dark and dense we could not see any light through the sight glass. I was wondering if anyone on this forum had any recommendations.

http://www.jmcanty.com/itemDetail.aspx?itemId=TA7462-1

Thanks,
Cara


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## AnAppleSnail (Nov 12, 2013)

Let's think about the light you'll need. You're right, LED light strips are pretty dim.

How uniform does the illumination need to be? How transparent is your NTO? A quick web search showed that N2O4 could range from clear to dark brown.

What part of the world are you in? If the US, can you go cowboy and buy a flashlight or two to test output needs?

If I were doing this I would start with a selection of flashlights shining through the back window. If a small source like that works, I might just bodge together an LED on a heatsink, with a driver and power supply to stick on the back window. What about a standard A19 (Light bulb socket) light behind the unit?


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## HarryN (Feb 3, 2014)

In order to see bubbles, their has to be a light absorbtion contrast between the bubbles and the fluid. I have not worked with NTO, but similar brownish / red fluids can be a real challenge.

Perhaps a very bright monochromatic source (example red light in the 615 - 650 nm range) which is highly collimated might help. Do you have a light absorbtion / transmission spectrum for NTO ? Maybe there are some interesting spectrum gaps which can be used ?


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## HarryN (Feb 3, 2014)

Perhaps try some of the LED arrays from LEDEngin, they might be very close to what you are after.


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