The generation mechanism and (transmission) characteristics of static electricity, and the structure of electrostatic coal powder concentration transmitter have been introduced.

To the balance-structure, on the one hand, the right sense organ is important to the system performance, for it directly getting the measurement signal.

The principle, structure of the NBT-1 model of density adjusting unit were introduced. It can form a complete set with the density testing meter to control the density of the paper pulp.