In terms of gas supply, the kitchen should maintain negative pressure, but the negative pressure value should not exceed 5Pa. If the pressure is positive, the smell of smoke in the kitchen will spread to the restaurant, causing discomfort to customers; But if the negative pressure is too large, the furnace will catch fire, which will affect the combustion effect of the furnace. Kitchen air supply system usually refers to outdoor fresh air air conditioning air supply, which is considered as 80%~95% of the exhaust air volume.

The intake speed of the engine is generally 0.5m? /? S, 5m throat? /? S, the exhaust velocity through the pipeline is generally not less than 10m m? /? S, usually 10m? /? s~ 16m？ /? S, the wind is too low. Attached to the pipe. The greater the wind speed in the pipeline, the greater the noise and vibration. However, the air supply speed of the pipeline can be low, and the wind speed behind the fume hood can be greater than that in front of the fume hood.