为什么要使用SWA03探头?

2005-03-30 12:49

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资料摘要：

SWA03是一款专用于微风速测量的探头. 它的测量下限为0.05M/S. 并可以计算出测量点的人体热舒适度. 欧盟ISO7726技术委员会在2001年曾对市场上主要的微风速探头作了一个技术评判, 结果只有三家公司能通过ISO7726的标准并准许在欧洲市场上进行销售. 其中SWEMA 公司的SWA03综合指数为这三家之冠. 那么为什么对微风速的测量要求如此之难呢? 根据ISO7726标准, 一款合格的微风速探头必须满足下列几个条件: 1. 它对风的方向必须是不敏感的, 这是因为越是速度低的风, 它便越容易受周围气流的影响以至于它的方向会漂浮不定. 2. 它的响应时间必须小于0.5S,即在0.5S内探头必须能跟踪风速瞬间变化的67%. 这同样是由于微弱气流的风速大小是极易受外界影响而产生剧烈的变化. 比如一般的室内气流总是在0.05 – 0.25 M/S 之间跳跃. 变化率达到500%! 3. 基于同样的理由, 微风速的测量频率也不能低于2HZ. 然而, 按常规探头设计的思路, 第一个要求与第二个及第三个要求是相互冲突的. 万向性风探头一般都做得较粗大以求得能收集到所有方向风的信息, 但是探头越粗大, 它的响应时间便会急剧增大及测量频率会急剧减小(热惯性增大)。 SWEMA 公司的专利设计彻底突破了传统设计的思路, 使得在这三者之间取得了完美的平衡. ( 方向对测量的影响不超过3%,最小时间常数为0.1S, 最大测量频率为10HZ!)。因此，SWA03是目前世界上最好的便携式微风速探头。

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