The biggest advantage of the top feed top return air form is that the project is simple and the cost is low, but the direction of dust particle settlement in the air of this air flow type is contrary to the updraft of the return air, affecting the timely discharge of dust particles in the air, especially large particles of dust, so it is not suitable for medical clean rooms (areas) with high air cleanliness.
顶送顶回风形式的最大优点是工程简单、造价低，但此种气流流型空气中尘粒沉降的方向与回风的上升气流相逆，影响空气中的尘粒尤其是大颗粒尘埃的及时排出，所以它不适用于空气洁净度等级高的医药洁净室（区）。
For the room with dust emission or harmful substances that are heavier than the air in the production, even if the air cleanliness level is not high, it can not be used in the form of top feed top return air.
对于生产中有粉尘散发或存在重度大于空气的有害物质的房间，即使空气洁净度等级不高，也不能采用顶送顶回风形式。
