Research on method for detection of harmful gases in livestock based on open path laser absorption spectrum

Abstract

The breath and feces of livestock and poultry will produce harmful gases such as ammonia, hydrogen sulfide and carbon dioxide. When the concentration of these gases exceeds the standard, they will seriously harm the health of livestock and poultry and even keepers. Fast and accurate monitoring of these harmful gases is of great significance in improving the health status of animals and keepers. Laser spectroscopy technology is an effective means of gas detection. Because of its high sensitivity and selectivity, it is widely used in gas monitoring. However, the currently adopted method of pumping sample gas detection based on the long optical path gas absorption cell is susceptible to the influence of the high ash and high humidity environment of the livestock and poultry house, causing detection errors. Open path laser absorption spectroscopy technology does not require a gas absorption cell to detect the gas concentration in free space. Based on this principle, this paper develops out the research on the open path laser absorption spectroscopy detection method for harmful gases in livestock and poultry houses, focusing on the design of laser collimation system, laser reflection system, laser focusing system, and laser detection system. The ammonia gas was used as the detection object to verify the feasibility of detecting harmful gas in livestock and poultry houses with open path laser absorption spectroscopy.