Electric butterfly valve is one of the regulating valves with simple structure. It can be opened and closed through the valve shaft. If we are clear about its function, it will be more effective when we use it. The understanding of advantages and disadvantages enables us to develop strengths and avoid weaknesses in specific operations. 　　

When considering the use of these small flow control valves, the selection criteria are quite different from those of the conventional control valves. For example, the friction loss connected in series with the control valve is very small, and there is no adverse pump head characteristics, and no real equal percentage characteristics are required. The main design problem is to carefully study the actual required flow range. The smaller the CV value, the more theoretical it becomes. They are useful as indicators of flow capacity, but their accuracy and repeatability are questionable, because in many cases, since the fluid passing through the throttling part may be laminar flow, or may be a mixture of laminar flow and turbulent flow, this mixed flow changes with the change of valve stroke or flow regulation.