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在用节流式变风量装置的可变风量系统中,风管内的压力常会随负荷的增减而变化。显然,这类系统的正常运行需具备一项必要的条件,就是变风量装置必须兼有某种自身的静压调整机能。具体说,节流式变风量装置要有一种所谓恒定风量的特性,在即使风管内的压力发生变化情况下,也能根据自动控制器的要求提供一定的风量。这也是它和历来惯用的一般电动风阀所不同的地方。现就文氏风阀的定风量原理作一简要说明:在送风系统中,风管的阻力R与风量Q的二次方成正比例。可用通过坐标原点的二次方程曲线来表示。如改变风管系统的形状、尺寸以及阀门的开度等,便可相应地得到一
In a variable air volume system using a throttling variable air volume device, the pressure in the air duct often changes as the load increases or decreases. Obviously, the normal operation of such systems requires a necessary condition that the variable air volume device must have some kind of own static pressure adjustment function. Specifically, a throttling variable air volume device has a so-called constant air volume characteristic and can provide a certain amount of air flow according to the requirements of the automatic controller even if the pressure in the air duct changes. This is also where it differs from the usual conventional electric dampers. A brief description of the principle of the constant air volume of the Venturi valve is given below: In the air supply system, the resistance R of the air duct is proportional to the square of the air volume Q. It can be represented by a quadratic curve through the origin of coordinates. If you change the shape, size, and valve opening of the air duct system, you can get a corresponding