Kitchen lampblack will harm the respiratory system of human body. The purpose of installing lampblack machine is to smoke lampblack during cooking and reduce indoor pollution. Therefore, when selecting models, we should first choose ones with high smoke exhaust efficiency.

廚房的排煙系統主要由集煙罩、排煙管道、油煙凈化器、排煙和廚房整體補風裝置構成。其主要原因有以下幾種：

The smoke exhaust system of the kitchen is mainly composed of smoke collecting hood, smoke exhaust pipe, oil fume purifier, smoke exhaust and overall air supplement device of the kitchen. The main reasons are as follows:

1、主排煙管道通風面積不夠，氣體流速過大。根據工程經驗，排煙主管道內風速不能超過15m/s。否則在運行一個時期以后，很容易造成排煙系統不通暢。在油煙凈化器的運行實踐中，大部分案例都是因排煙管道通風面積不足引起的不通暢，管道內氣體的流速都在15m/s以上。

1. The ventilation area of the main smoke exhaust pipe is insufficient and the gas flow rate is too large. According to engineering experience, the wind speed in the main smoke exhaust pipe shall not exceed 15m / s. Otherwise, after a period of operation, it is easy to cause the smoke exhaust system to be blocked. In the operation practice of oil fume purifier, most cases are blocked due to insufficient ventilation area of smoke exhaust pipe, and the flow rate of gas in the pipe is more than 15m / s.

2、排煙管道由于要穿過建筑梁而使管道通風截面積變小，截面上阻力增加，造成氣流不通暢。

2. As the smoke exhaust pipe passes through the building beam, the ventilation cross-sectional area of the pipe becomes smaller and the resistance on the cross-section increases, resulting in unobstructed air flow.

3、排煙管道在穿過建筑梁或躲避其它設備管道時，排煙管道中的一段會低于整體排煙管道平面。在使用一段時間后，由于油水混合物會積聚在較低的那段排煙管道中，直接影響排煙通暢。

3. When the smoke exhaust pipe passes through the building beam or avoids other equipment pipes, one section of the smoke exhaust pipe will be lower than the plane of the overall smoke exhaust pipe. After using for a period of time, the oil-water mixture will accumulate in the lower section of the smoke exhaust pipe, which will directly affect the smoothness of smoke exhaust.

4、不同樓層的廚房油煙通過同一主管道排出，離出口近的樓層廚房排煙效果較好，而較低樓層的廚房排煙不通暢。

4. The kitchen fume of different floors is discharged through the same main pipe. The kitchen smoke exhaust effect of the floor close to the exit is better, while the kitchen smoke exhaust of the lower floor is not unobstructed.

其次,要選擇負壓大的。因為飯店廚房排煙設備的負壓越大,吸煙能力越強.如您所述,目前市場上的油煙機分為平板式、半深型、深型和柜式等類型,它們因結構的不同產生的"負壓區"也不同。

Secondly, we should choose the one with large negative pressure. As you mentioned, the range hoods on the market are divided into flat type, semi deep type, deep type and cabinet type, and their "negative pressure area" is also different due to different structures.