The precision of liquid column manometer was described. The correct use method and error correction of U tube manometer and double tube differential pressuregauge were analysed.
叙述了液柱式压力计的精度，对U形管压力计和双管差压计的正确使用方法及误差修正做了简要分析。
2
For improving automatic gauge control precision and quality of the whole strip, FMN is proposed to correct gap of the rolling by fast hydraulic pressure system.