一、设计演变在1969年以前,大多数实验室通风柜都单独装有排风扇,该排风扇只能以0.5米/秒(100英尺/分)的恒定风速流经通风柜的开口。因此实验室的气流很难控制,而且能耗较高。到七十年代中期,随着变风量系统的出 First, the design evolution Before 1969, most laboratory fume hoods were equipped with a separate exhaust fan that could only flow through the fume hood openings at a constant air velocity of 0.5 m/s (100 ft/min). Therefore, the air flow in the laboratory is difficult to control and the energy consumption is high. By the mid-1970s, with the VAV system