Previous in Forum: Starting a Calibration Company   Next in Forum: Power Plant Alternators
Close
Close
Close
4 comments
Member

Join Date: Mar 2007
Posts: 8

Bubble interference in Turbidity measurement

02/13/2010 7:02 AM

I work in the QMI unit of my company and we are facing the problem of erratic readings from an Optek turbidity analyzer (nephelometer) due to bubble interference. The bubbles disperse the light from the light source and increase the turbidity. We have a debubbler installed but it doesn't seem to be effective enough. I have extensively Googled the problem but am yet to get a specific solution. Can anybody with experience or info please help out. Thanks.

Register to Reply
Pathfinder Tags: bubble nephelometer Turbidity
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru
Hobbies - DIY Welding - New Member

Join Date: Apr 2008
Location: Bristol, Tennessee
Posts: 1176
Good Answers: 57
#1

Re: Bubble interference in Turbidity measurement

02/13/2010 11:35 PM

Have a restrictor after the meter to raise pressure in the meter. Make sure pressure is not dropping before or inside the meter. Pressure should eliminate bubbles, and not affect turbidity readings.

__________________
mike k
Register to Reply
Power-User

Join Date: Dec 2006
Posts: 442
Good Answers: 32
#2

Re: Bubble interference in Turbidity measurement

02/14/2010 10:52 AM

You may be able to eliminate the bubbles by placing the liquid under a vacuum before putting in the instrument. This may cause the bubbles to grow to a large enough size to come to the surface and pop.

You may also try putting the liquid in an ultrasonic cleaner to remove bubbles.

Register to Reply
Member

Join Date: Feb 2010
Location: Kailua-Kona, Hawaii
Posts: 5
#3

Re: Bubble interference in Turbidity measurement

02/14/2010 11:42 AM

Increase the surface energy of the inside of the analyzer (may be made of plastic) by surface treatment. Then the liquid will "wet out" and no more bubbles!

Register to Reply
Guru

Join Date: Feb 2009
Location: Tamilnadu, India
Posts: 837
Good Answers: 42
#4

Re: Bubble interference in Turbidity measurement

02/15/2010 2:04 AM

The bubbles in the water sample could be due to the presence of agitation or surfactants present in water.

Any effort to destabilize bubbles will disturb the estimation of suspended solids.

You may try the following.

*Add few drops of Defoamer[silicon or fatty oil based or solvent based- bare minimum to avoid suspended impurities getting along. wait for some time to see the foam/ bubbles destabilize. (OR)

*Add few drops of Hydrogen peroxide so that all bubbles move to top layer.(or]

*Acidic pH can also help tp some extent.(OR}

*Another simplest idea is to cool the water sample in fridge so that so that all bubbles collapse out due to shrinkage.{or]

*Similarly heating can also de aerate the bubbles.

I Think you may proceed on these principle and minimize the bubble error.Remember all conditions to apply only turbidity analysis and the water sample need not be used for other tests because of it"s added contents or changed physical/ chemical conditions.

__________________
Nature is so graceful and naked. Human possession is ridiculous.
Register to Reply
Register to Reply 4 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

leewil (1); mike k (1); s.udhayamarthandan (1); Tad (1)

Previous in Forum: Starting a Calibration Company   Next in Forum: Power Plant Alternators

Advertisement