sump level with oil, water and some foam

N

Thread Starter

newbie

the sump contains varying proportions of oil and water with a slight foam. the plant decided to replace the float type with a new ultrasonic level sensor which has an erattic level detection. is it the foam throwing the level out and what type of technology would you suggest?
 
M

marc sinclair

Hi, Floats are great, I've just replaced two ultrasonic and two radar sensors with floats. The floats I've used will probably need replacing every 5 years, but I can afford (even with my time) to replace them 4 times a year for the cost of the 'advanced solutions'

Marc Sinclair
 
If you can, change the damping (slower) on the ultrasonic sensor to reduce unwanted fluctuations in your display and output. I would try that first. Ultrasonics tend not to be a good system in an application that produces surface foam. Radar would also get confused if the foam is wet. I would switch back to floats if that worked for you. Here's a cheap float that works quite well.

http://www.drlevel.com/float_gravity.htm
 
M

marc sinclair

Hi,

Beware of 'cheap floats', pay attention to the flexible cable insulation material and its compatibility with fats.

marc
 
Thank you for the insight. In my research the float system seemed to be the best also. The plant wants to eliminate maintenace on the level system, however, and I believe that the ultrasonic may require more maintenance than the floats. Thanks again.
 
Ultrasonics do not require maintenance if you apply them to applications that are black and white. Your application produces foam which is not a good application for ultrasonics.

As far as the drlevel float is concerned, it's the best bang for the buck that I am aware of. The hermetically molded, double chamber and switch works quite well. I dissected one of these floats one time and it was as described. As the other poster mentioned, float cables can be the weak link due to the environment that it has to be in. As stated before, floats can easily be replaced for the cost of a contactless solution.
 
I forgot to mention that if you do go back to a float again, try to find one that is not polypropylene. You need one that is made out of Kynar since you also have oil in the mix with your water. Oil will break down polypropylene eventually. The drlevel float is made out of polypropylene so that would not be a good fit for you.
 
I very much agree that because of presence of few substance in waste water, polypropyelene, or PVC coated tends to get hardened and after some time cable will entangle and it may cause overflow. try float with HR HY (hypalon) material, which doesn't get hardened because of its properties. Hypalon is very much popular in river craft, boat manufacturing. Try http://www.atmi.fr or http://www.bestobell.com (in Canada). It has solved the problem of one of my customers (regional waste water treatment plant).

All the best.
 
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