PURPOSE: A sector plate adjuster is provided to reduce size and weight of the cooling system, while allowing for ease of control of gas leakage and effectiveness of maintenance. CONSTITUTION: An air preheater(1) comprises a sector plate(5) arranged on a rotor(3) and which divides a waste gas outlet side and an external air inlet side of the rotor. A sector plate adjuster(21) is connected to the sector plate in the periphery of the lower end of a bearing housing(9) in such a manner that the sector plate is movable in a vertical direction. The sector plate adjuster includes a bolt connected to the sector plate through a link plate coupled on the sector plate; a support plate for supporting the bolt through a nut where the bolt is screw-coupled; and an outer frame surrounding the link plate in such a manner that a support plate supports the bolt.
