LYNDVIS transmissive smokemeter module is a distributary high-performance smokemeter module independently developed by Laoying. It can meet the technical requirements of JJF 1482-2014, JJG976-2010 standards. It has three types of readings includingopacity N, absorption coefficient K and standard optical channel effective length absorption ratio Ns, it also supports N value calibration, smoke temperature calibration and other functions.

The smokemeter module is an instrument based on the physical principle of light attenuation. A beam of light is shielded by particles of waste gas, and the intensity of the beam is related to the concentration of particles. Their relationship can be expressed by Lambert-Beer law. Opacity N is also called absorption ratio, which indicates the ratio of the absorbed luminous flux to the incident luminous flux of light from the light source and going through a dark channel filled with smoke.

The module is designed on the distributary principle, and the exhaust gas is extracted by dynamic pressure (the exhaust gas is brought into the gas chamber by the exhaust pressure of the motor vehicle for measurement). The degree of visible pollutants discharged is evaluated according to the light intensity detected by the module. The working process is shown in Figure 1.