Aqueous urea solution is prepared by mixing urea with deionized water in fixed proportions (with a tolerance of ± 1.5%). The urea solution can be contaminated with the presence of sodium, calcium, magnesium, potassium, Phosphor and other salts. Low quality aqueous urea solution in terms of mineral contamination & changes in concentration needs to be diagnosed instantaneously and should also alert the end user accordingly.
Refractometers are often used for measuring concentration of the urea solution against a specification of X%±1.5. This however, is an offline diagnosis. In addition, detection of contamination (because of Na, K, Ca, Mg, P etc) is not possible with Refractometers.
An ideal system would measure contamination and incorrect concentration levels online and alerts the user instantaneously. This system is intended to be deployed inside the storage tank made of plastic. Any deviation from the specified levels should be indicated instantaneously to the user via digital mode. The output (pass/fail) should also be integrated in the on-line detection system.