Design of pump suction ammonia detection device based on TDLAS technology

The concentration of ammonia will affect the growth and health of animals. At present, the ammonia sensor is widely used in electrochemical detection, but it has defects like easy aging, short lifetime, slow response, low precision and requirement for calibration. The ammonia concentration is more difficult to measure because ammonia is easy to react with water molecules in the air. Aiming at this problem, this paper designs a kind of pump suction ammonia detection device based on TDLAS spectrum absorption technology. Based on Beer-Lambert's law, the DFB laser with wavelength of 1512.2nm was chosen as the ammonia gas detection light source. Wavelength modulation spectroscopy is used to demodulate the output signal of the detector. The precise temperature control and heat dissipation structure of the laser and the long path gas absorption cell are designed. Under the condition of high speed gas flow by Pump Suction, the concentration of ammonia in the gas absorption cell is consistent with the faster speed, and the effect of adsorption is reduced. The results show that the device is effective in piggery.