清浄度立ち上がり特性によるクリーンルームの性能評価に関する研究 : 一方向流方式の場合

抄録

The air cleaning ability of a unidirectional flow cleanroom system is examined experimentally in regard to various air-supply velocities, the size of the vent of the ceiling and of the floor and the relations between them. The change of particle concentration is referred to as the 'decay of particle concentration' judged from the point when the system begins operation. The pattern and the time of this decay indicates the system's air cleaning ability. The experiment shows that although the configuration of the cleanroom is a unidirectional flow, the property of controlling contamination is in three degrees, namely, unidirectional flow, 'perfect diffusion', and 'imperfect discharge' according to the velocity. The latter two are referred to as non-unidirectional. Clean-up time is calculated using two kind of equations. The lower limit of the vent's size is obtained. For the ceiling inlet, 50% of the size ratio constitutes the lower limit necessary to maintain the cleanliness class 5 in JIS B 9920, to the contrary to the limit of 14% for the floor outlet.