In drainage of agricultural lands, a filter or gravel envelope is used to prevent the entrance of fine sand and silt into the drains.
在农田排水中常常采用砾石或过滤层来防止粉细砂和泥沙进入排水沟。
A metal filter assembly used to support and retain the sand placed during gravel pack operations.
在砾石充填作业期间放置的为支承和挡住砂子所用的由金属制成的过滤装置。
The process includes the waste purification from oil emulsion in Tilted-Plate Separator and the suspension separation in the downward-flow sand-gravel filter.
处理方法包括使用倾斜盘式分离器分离油乳化剂，使用下流式砂砾过滤器分离悬浮颗粒物。
In a vertical filter made up of sand and gravel more than 80 % of the total nitrogen at 50 cm ground depth consists of nitrate, whereas only roughly 10 % consist of ammonium.
垂直过滤系统由沙、卵石组成，在离地面50厘米的区域，氮主要以硝酸盐的形式存在(80 %)，大约只有10%的氮是以铵的形式存在。
In a vertical filter made up of sand and gravel more than 80 % of the total nitrogen at 50 cm ground depth consists of nitrate, whereas only roughly 10 % consist of ammonium.
垂直过滤系统由沙、卵石组成，在离地面50厘米的区域，氮主要以硝酸盐的形式存在(80 %)，大约只有10%的氮是以铵的形式存在。
应用推荐