The system for monitoring of the water mass fraction in the urea melt(for a single channel measurement of concentration) consists of:
- concentration sensor;
- spark protection unit;
- unit of signal normalization;
- valve of refrigerant supply; industrial PC with input-output boards.
Principle of the system:Method of determination of the water mass fraction consists in:
- supplying of refrigerant to the concentration sensor and measuring the temperature inside the sensor during cooling and melt crystallization;
- analysis of the measured dependence “temperature – time” in the “sliding window”, crystallization temperature definition;
- calculation of the water mass fraction in the urea melt.
After determining of the crystallization temperature supply of the refrigerant stops, the environment inside the concentration sensor renews and the cycle repeats.
Time of cycle is about 10 min