1. Case analysis

A restaurant in Qingdao features a next-year island-style smoky hood. One 7.5kW(450#) high pressure air cabinet (19500 flow) and one 1.5kW external rotor air cabinet (5500 flow) for the fresh air system. Fresh air mainly depends on the natural air supply of doors and windows, and the flue gas exhaust effect is not good. (Pipe cross-sectional area, pressure and flow are sufficient)

2. Major issues: Flue gas venting and spillage

after turning on the air conditioner, the kitchen will generate negative pressure, and the airflow will flow to the kitchen through the mechanical and natural air supply. To be precise, the air will flow from the position of the door and window to the direction of the smoke hood. Due to the natural air replenishment factor and the high flow rate, the flow rate will be too fast, which will offset the upward airflow within the normal suction range of the smoke hood, resulting in the upward direction of the airflow change and tilt, resulting in smoke overflow and unsatisfactory smoke Exhaust effect. Ordinary wall-mounted smoke hoods may also have a slight impact, but the impact is not significant, because the upward airflow blowing to the wall position will return and enter the normal suction range of the smoke hood.

3-Solution

increasing the mechanical air supply coefficient can reduce the negative pressure in the kitchen and reduce the natural air supply coefficient, which will greatly improve the flue gas exhaust effect.

4-Precautions

ordinary island-style open flue gas exhaust must pay attention to the direction of cross wind; cross wind: natural supplementary air turbulence and airflow turbulence caused by human channels may have a certain impact on flue gas exhaust. The best solution to avoid pedestrian interference is to build zones with a height of about 1.2 million.