通风管道有哪些机械通风原则呢？
What are the mechanical ventilation principles for ventilation ducts?
想要实现通风管道的通风，就可以利用机械通风，也可以利用自然通风来实现。按作用机理不同，通风可分为稀释通风和置换通风两类。
To achieve ventilation through ventilation ducts, mechanical ventilation or natural ventilation can be used. According to different mechanisms of action, ventilation can be divided into two categories: dilution ventilation and displacement ventilation.
1、稀释通风
1. Dilution ventilation
稀释通风又称混合通风，即送人比室内污染物浓度低的空气与室内空气混合，以此降低室内污染物的浓度，达到卫生标难。
Dilution ventilation, also known as mixed ventilation, refers to mixing air with a lower concentration of indoor pollutants, in order to reduce the concentration of indoor pollutants and meet hygiene standards.
2、置换通风
2. Displacement ventilation
在置换通风系统中，新鲜冷空气由房间底部以很低的速度送入，送风温差仅为2—4Y。送入的新鲜空气因密度大而像水一样弥漫整个房间的底部，热源引起的热对流气流使室内产生垂直的温度禅度，气流缓慢上升，脱离工作区，将余热和污染物推向房间顶部，由设在顶棚上或房间顶部的排风口直接排出。
In a displacement ventilation system, fresh cold air is fed in at a very low speed from the bottom of the room, with a temperature difference of only 2-4Y for the supply air. The fresh air sent in is as dense as water and permeates the entire bottom of the room. The heat generated by the heat source creates a vertical temperature gradient in the room, causing the airflow to slowly rise and detach from the work area, pushing waste heat and pollutants towards the top of the room, which is directly discharged by the exhaust vents located on the ceiling or at the top of the room.
室内空气近似活塞状流动，使污染物随家庄电动伸缩门 保定桌椅  保定水处理设备 河北机械加工  保定养老院  保定防水空气流动从房间顶部排出，工作区基本处于送入空气中，即工作区污染物浓度约等于送人空气的浓度，这是置换通风与传统的稀释通风的区别。在通风管道中，显然置换通风的通风效果比稀释通风要好。
The indoor air flows in a piston like manner, allowing pollutants to be discharged from the top of the room with the air flow. The working area is basically in the incoming air, which means that the concentration of pollutants in the working area is approximately equal to the concentration of the incoming air. This is the difference between displacement ventilation and traditional dilution ventilation. In the ventilation duct, it is obvious that the ventilation effect of displacement ventilation is better than that of dilution ventilation.