Smoke meter classification and principle

There are two main instruments for measuring smoke, one is a filter paper smoke meter, and the other is an opaque smoke meter.

The filter paper smoke meter uses a piston to extract a certain amount of exhaust gas and passes it through a certain area of ​​white filter paper. The carbon particles in the exhaust gas are adsorbed on the filter paper to make the filter paper black. The degree of smoke was then assessed by measuring the absorbance on the filter paper with a photodetector. Some of the indicator ammeters of the photoelectric detection device are expressed in 0 to 10 RB wave units, and some are expressed in terms of pollution degree (%). When the Bosch unit is used, the indication value is "0" indicating the smoke degree of the all-white filter paper, and "10" indicates the smoke degree of the all-black filter paper. The filter paper smoke meter can only sample the exhaust gas and cannot make continuous measurements, but it can shorten the sampling time through automation.

The principle of the opaque smoke meter is that before the measurement, it is first purged with air, and then part or all of the smoke is continuously passed through the smoke meter so that the light passes through the introduced exhaust gas, and the photocell can measure the light. The rate of decay, through the recorder, gives an indication of the evolution of the smoke over time. The smoke measurement is represented by a linear index of zero for smokelessness and 100 for total blackness.