屋頂(ding)(ding)風(feng)(feng)(feng)(feng)(feng)機(ji)是安裝(zhuang)在屋頂(ding)(ding)上(shang)進行排風(feng)(feng)(feng)(feng)(feng)換氣的(de)(de)(de)，由(you)于安裝(zhuang)使(shi)用(yong)環(huan)境的(de)(de)(de)特(te)殊性，決(jue)定了風(feng)(feng)(feng)(feng)(feng)機(ji)使(shi)用(yong)材質和結構的(de)(de)(de)特(te)殊。 屋頂(ding)(ding)風(feng)(feng)(feng)(feng)(feng)機(ji)設置停機(ji)后防(fang)止空氣倒流的(de)(de)(de)裝(zhuang)置，因(yin)為在熱壓(ya)作用(yong)下風(feng)(feng)(feng)(feng)(feng)機(ji)高速旋轉(zhuan)，造成風(feng)(feng)(feng)(feng)(feng)筒內風(feng)(feng)(feng)(feng)(feng)速增(zeng)大很多，風(feng)(feng)(feng)(feng)(feng)機(ji)倒轉(zhuan)對(dui)電(dian)(dian)機(ji)的(de)(de)(de)啟動很不(bu)利(li)，可能因(yin)啟動電(dian)(dian)流過大而損壞。屋頂(ding)(ding)風(feng)(feng)(feng)(feng)(feng)機(ji)在設計時應該具(ju)有可靠(kao)的(de)(de)(de)防(fang)雨(yu)、防(fang)飛(fei)雪(xue)、防(fang)風(feng)(feng)(feng)(feng)(feng)沙(sha)的(de)(de)(de)性能，風(feng)(feng)(feng)(feng)(feng)雪(xue)和風(feng)(feng)(feng)(feng)(feng)沙(sha)不(bu)像(xiang)雨(yu)水那樣(yang)，因(yin)為飛(fei)雪(xue)和風(feng)(feng)(feng)(feng)(feng)沙(sha)不(bu)僅會(hui)從上(shang)部進入風(feng)(feng)(feng)(feng)(feng)機(ji)，在室外風(feng)(feng)(feng)(feng)(feng)速達到一定強(qiang)度下，還(huan)可能從下部進入風(feng)(feng)(feng)(feng)(feng)機(ji)。