The load perturbation of both of the turbines is large during the course of switch between single valve and sequencing valve,which had passive influence on the safe operation of units.

It is described that the two 600MW turbine units could not be switched to sequence valve control mode and had been always running at single valve mode because of the problems of the turbine structure,installation and operation,and therefore,the efficiency of the units was at depressed level.

The anomalous phenomenon occurred after adopting sequencing valve steam distribution mode instead of single valve mode in 2×600 MW supercritical turbine of Guohua Taicang Power Generation Co.

Oil-immersed spring mechaical breather valve;

To ensure the safety of the tank,the management of the breather valve and flame arrester is strengthened by examining and repairing the tank and accessories in time so as to use it reasonably.

Flame trap of breather valve of road tank was designed in order to control the hidden hazards of inflammable and explosive of breather valve of road tank.

Author introduces the existing problems in use of both breath valve used in domestic oil tank with internal dome roof and assembly - disassembly type inner floating roof made of aluminum, moreover author analyses the reason of problems caused and indicates the notices, standard and codes to be obeyed during selecting the breath valve or inner floating roof.