filter sand meaning in Chinese

滤砂
滤沙

Testing of filter sands for air - raid shelter ventilation - determination of flow resistance
防空洞通风用滤砂试验.气流阻力测定
For economic reasons , we did much of the heavy work ourselves - transporting cement , sand , lime , and bricks from the foothills , tearing down the hut , mixing cement , filtering sand , and carrying bucketfuls of building material
为了节省开支，许多粗重的工作例如下山运水泥沙白灰砖，拆棚子拌水泥筛沙提灰桶等工作，我们都亲自动手。
Manufactures : automatic softener consecutive water supply , inter - current water supply , meter and timer style , automatic filters sand filter , carbon filter , automatic desalination systems and automatic water purification system
水处理设备及系统有：全自动软化水装置连续供水及间断供水流量型及时间型全自动过滤水装置碳滤砂滤全自动除盐水装置全自动纯水装置。