The function characteristics of primary air and two primary air of boiler：

For pulverized coal boiler: the primary air is used to transport and dry pulverized coal, and provide oxygen for volatile combustion in pulverized coal; the secondary air plays a role of combustion support, providing sufficient oxygen for pulverized coal combustion. For CFB boiler: primary air plays the role of fluidizing materials; secondary air plays the role of combustion support.

Flue gas characteristics: the shape of the pipeline is mainly square and round, the composition is complex, the particle type impurities are more, the micro negative pressure, the pipeline flow rate is small, etc.

Difficulties in measurement of large diameter air volume：

1 / the measured pipe diameter is large.

2 / there is a certain amount of pulverized coal impurities in the air.

3 / the stability of small flow measurement is poor.

Target features：

Plug in installation, simple and convenient installation, saving installation cost.

The advanced anti blocking structure design has no effect on the environmental measurement with large impurity content.

The principle of strain force type, with high sensitivity, can measure ultra-small flow, and its low flow rate is 0.005m/s.