PROBLEM TO BE SOLVED: To provide an air conditioning operation state changeable system capable of preventing a substantial variation of indoor air pressure of a clean room during changing-over operation from a full-environment air operation to a circulating operation.SOLUTION: An air conditioning operation state changing-over system 10A in its changing-over operation performs opening operation means for gradually opening a revolving blade 24 of the first motor damper 17 kept in its full-closed state to make its full-open state and performs first opening degree keeping means for interrupting the opening operation means and keeping an opening degree of the revolving blade 24 of the damper 17 at that time when the indoor air pressure in a clean room 11 measured by a pressure sensor 18 exceeds over the upper limit value of a desired room pressure or when the indoor air pressure in the clean room 11 measured by the pressure sensor 18 is less than a lower limit value of the desired room pressure during a period from a starting of the opening operation means to a time in which the revolving blade 24 shows a prescribed degree of opening.COPYRIGHT: (C)2015,JPO&INPIT【課題】全外気運転から循環運転への切替運転中におけるクリーンルームの室内気圧の大きな変動を防ぐことができる空調運転形態変更システムを提供する。【解決手段】切替運転において空調運転形態変更システム10Aでは、全閉状態にある第1モーターダンパ17の旋回羽根24を次第に開いて全開にする開動作手段と、開動作手段の開始から旋回羽根24が所定の開度になるまでの間に、圧力センサ18が計測したクリーンルーム11の室内気圧が目標室圧の上限値を上回った場合、または、圧力センサ18が計測したクリーンルーム11の室内気圧が目標室圧の下限値を下回った場合、開動作手段を中断してその時点におけるダンパ17の旋回羽根24の開度を維持する開度第1維持手段とを行う。【選択図】図1
