The starting conditions for medium pressure centrifugal blowers are usually divided into lubricating oil coolers with a temperature greater than 35°C. During operation, the lubricating oil manifold pressure will be greater than 0.25 MPA (G), and the inlet vane position of the medium pressure centrifugal blower will be slightly opened. The position of the blower vent valve (BOV) is fully reopened, the unit has no interlock shutdown, and the DCS allows starting and other conditions.
The loading process of the compressor of the medium-pressure centrifugal blower is an unloaded state, and the effective pressure is transferred to the constant pressure control to reach the pressure setting value. When the equipment supplies air to the system, the system setting pressure is greater than the actual pressure. At that time, the air intake guide vane will gradually open from 10% of no-load, and the motor current will increase.
When the current exceeds 230A, the medium pressure centrifugal blower starts to close the discharge valve to a certain extent. During operation, the inlet guide vane and the vent valve are adjusted together, so that the current of the motor can be maintained at 230A until the pressure rise of the third stage. High, the system pressure reaches the set value and enters the constant pressure control state.
The speed of the medium-pressure centrifugal blower during loading and whether it can be loaded successfully depends on the proportionality of the control parameters and the size of the integration time during operation. When the system demand is large, the integration time should be increased to reach the pressure setting value. Conversely, when the system demand is small, it should be adjusted smaller. Otherwise, it will be too sensitive, and it will cause the valve oscillation to fluctuate and fail to load.
The pressure blower of the medium-pressure centrifugal blower changes due to the air volume demand of the system. The task of the compressor is to be adjusted by the control system when the demand of the system changes, so that the system pressure can be kept constant, and thus the load can be increased to some extent. To the role of a constant pressure source, its control is accomplished by the common adjustment of the inlet guide vane and the vent valve.