1.主排气管的通风面积不够。

1. The ventilation area of the main exhaust pipe is insufficient.

根据工程经验，主管道风速不能超过 15m/s，否则在运行一段时间后很容易使排烟系统通畅。在油烟净化器的运行实践中，大部分情况是由于排气管通风面积不足所致，管道内气体流量在 15m/ s 以上。

According to engineering experience, the wind speed of the main pipeline cannot exceed 15m/s, otherwise it is easy to make the smoke exhaust system unobstructed after running for a period of time. In the operation practice of oil fume purifiers, most cases are caused by insufficient ventilation area of the exhaust pipe, and the gas flow rate in the pipeline is above 15m/s.

2.管道的横截面面积变小

2. The cross-sectional area of the pipeline decreases

由于需要通过建筑横梁，管道的通风截面面积变小，截面上的阻力增大，导致气流不顺畅。

Due to the need to pass through the building crossbeam, the ventilation cross-sectional area of the pipeline decreases, and the resistance on the cross-section increases, resulting in uneven airflow.

3.使用排水管后集料的积聚

3. Accumulation of aggregates after using drainage pipes

当排烟管通过建筑物横梁或避开其他设备管道时，排烟管的某一部分将低于排烟管的整体水平。使用一段时间后，由于油水混合物将积聚在排气管的下部，排烟将受到直接影响。

When smoke exhaust pipes pass through building beams or avoid other equipment pipelines, a certain part of the smoke exhaust pipe will be lower than the overall level of the smoke exhaust pipe. After a period of use, due to the accumulation of oil-water mixture in the lower part of the exhaust pipe, smoke exhaust will be directly affected.

4.低排烟不平坦

4. Uneven low smoke exhaust

不同楼层的厨房烟气通过同一主管道排出，厨房出口附近的厨房排烟效果较好，但下楼厨房的排烟不顺畅。

Kitchen smoke from different floors is discharged through the same main pipeline. The kitchen near the kitchen outlet has a better smoke exhaust effect, but the smoke exhaust from the downstairs kitchen is not smooth.

5.建议安装排烟风扇

5. It is recommended to install a smoke exhaust fan

对于大排烟的厨房，还建议安装排烟风扇。有三种排烟风扇：轴流风扇、空气底盘和离心风扇。

For kitchens with high smoke exhaust, it is also recommended to install smoke exhaust fans. There are three types of smoke exhaust fans: axial fans, air chassis, and centrifugal fans.

一般情况来讲，通风管道在安装过程当中提前设计好当前厨房的规划，从而减少通风管道出现的排烟不正常状况

Generally speaking, ventilation ducts should be designed in advance during the installation process to minimize the occurrence of abnormal smoke exhaust in the kitchen