2. Working flow characteristics: analyze the flow characteristics obtained when the pressure difference between the front and rear ends of the control valve changes. It can be divided into linear characteristics, logarithmic characteristics, parabolic characteristics, etc. The parabola property is between straight and logarithmic. Through calculation and analysis, the linear characteristic control valve has strong regulation when working at small opening, and the relative flow rate of change is too intense to control. Small interference is easy to overcome, which causes system oscillation. At large opening, the relative rate of change, the regulation performance is weak, too slow, and large interference cannot be overcome quickly; Logarithmic characteristic means that the change value of relative flow caused by the change of unit opening is proportional to the relative flow at this point. Through calculation and analysis, the logarithmic valve has small magnification at small opening, moderate balance, and is conducive to operation and control. However, it has large magnification at large opening, and is sensitive and effective. It is a valve commonly used by Zui.

In the process of industrial automation control, electric butterfly valve is the most commonly used low-pressure valve. Under normal temperature or low pressure environment, electric butterfly valve has been widely used due to its good performance, especially in the water treatment and environmental protection industry, with a very high frequency of use. Next, let's briefly introduce the process characteristics of the device and the preparations that need to be done before installation for novice friends.