For shelters , the results show : 1 ) to reduce the raining drops entering into the inlet and to decrease the influence of the vortex , the declining angle of 45 is recommended for the shelters ; 2 ) it is better to choose those shelters which are longer 100 mm ~ 200 mm than the height of the inlets , as they may protect the room from rain 对于单侧百叶风口的挡雨板，计算表明: 1 )为了防止雨水随空气流入自然进风口，并且使风口尽量少受涡流区的影响，建议选用倾斜角度为45 “的挡雨板; 2 )建议选用长度比风口高度长100mm - - 200 “的挡雨板，可以较好的避免挡雨板过短将雨水带入室内和过长影响风口进风的情况。
When wind pressure of fan is deficiency or the inner sand layer of double disk is too thick , the tuyere of double disk will jam especially when moisture of sand is too high ; this jam must be treated by manually because the jam of green sand becomes very hard after air - dry and the system can not renew by itself 当鼓风机的风压不足或双盘内砂层过厚，双盘内风口会出现堵塞现象，尤其是砂子水分过高这种堵塞除非人工清理，其系统本身是无法恢复的，因为湿的砂子堵塞进风口干后会非常坚硬。
