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摘要

The present invention relates to a hydraulic system for controlling a blade angle of a fan in a large capacity boiler. The hydraulic system for controlling a blade angle of a fan in a large capacity boiler has a multiplexed proportional control valve instead of an existing mechanical control part of a control actuator. The hydraulic system for controlling a blade angle of a fan in a large capacity boiler comprises: a hydraulic control fluid block having two oil ports corresponding to oil supply ports of a piston shaft, sealings arranged in both sides of the oil ports, a first bearing cover formed in one end while having an oil seal for surrounding the piston shaft and a mounting unit, and a second bearing cover formed in the other end while having a mounting unit for mounting an LVDT displacement sensor; a hydraulic port connection pipe connected to the oil ports of the hydraulic control fluid block; the LVDT displacement sensor inserted along a central hole of the piston shaft instead of a feedback rod; and the proportional control valve mounted on the hydraulic port connection pipe. The present invention reduces a failure rate by simplifying a structure of the control actuator for adjusting a blade angle of a fan when the frequency and load of a system are changed and increases reliability and convenience according to the multiplexed composition of the proportional control valve; thereby reducing power generation costs and stably operating a power generation facility.