| 摘要 |
PURPOSE:To prevent contamination in a highly clean region due to approach of workers' bodies effectively, by providing a means, which changes the ratios of exhaust air quantities among a plurality of exhaust ports, and minimizing the quantity of flowing clean gas in the highly clean region. CONSTITUTION:Based on data from a sensor 18, the ratios of exhaust air quantities of exhaust ports (QE/QH) and [(QH-QE)/QH] with respect to diffused air into a clean region A are kept at preset steady ratios (QE/QH=K1) and [(QH-QE)/QH=K2], under the state workers and the like do not approach the highly clean region A. When the workers approach the region, the ratio of the exhaust air quantity at the second exhaust port 10 [(QH-QE)/QH] with respect to the diffused air into the clean region A is made to be the value (K2+DELTAK2), which is larger than the steady ratio K2 by a preset width DELTAK2. At the same time, the ratio of the exhaust air quantity at the first exhaust port 9 (QE/QH) is made to be a value (K1-DELTAK1), which is smaller than the steady ratio K1 by a preset width DELTAK1. In order to obtain these values, a damper 17 is automatically operated by a control device 19. |
