The flow characteristics of the electric control valve directly affect the control quality and stability of the system, so it needs to be selected correctly.
The flow characteristics of electric control valve are divided into ideal flow characteristics and working flow characteristics. The flow characteristic provided by the general manufacturer is the ideal flow characteristic, while the electric regulating valve needs the working flow characteristic in practical application. Since the pressure drop ratio S is less than 1, the working flow characteristic is convex. Therefore, when selecting the flow characteristics of the electric regulating valve, the selection of the working flow characteristics should be considered first. Then, select the ideal flow characteristics according to the actual application. The ideal flow characteristics commonly used in production are linear, equal percentage and quick opening characteristics. The quick-opening characteristic is mainly used for two-position control and program control. Therefore, the selection of the flow characteristic of the electric regulating valve usually refers to how to reasonably select the ideal flow characteristic of linearity and equal percentage.
When the electric control valve is actually used, the control valve is always installed in the process pipeline system, and the pressure difference before and after the electric control valve changes with the resistance of the pipeline system. Therefore, when selecting the flow characteristics of the regulating valve, not only the process characteristics, but also the piping conditions of the system should be considered.
An environmental protection company in Nantong, Jiangsu purchased a batch of regulating valves in 2014. According to the feedback of the on-site personnel, our regulating valve could not achieve the regulating effect. The company sent technicians to the site to check the reason, and later communicated with the on-site technicians. When purchasing, the purchasing personnel only provided the caliber and did not provide the relevant data, so the selected diameter was too large and could not be adjusted. This kind of problem can only be returned to the factory to reduce the diameter of the inner hole, which not only delays the user’s working conditions It also increases the cost of use, so when purchasing a control valve, be sure not to provide only the caliber because the parameters are not clear, and be sure to ask the on-site user some usage requirements (such as flow range, pre-valve pressure, post-valve pressure, flow rate, etc.). media, etc.) to avoid unnecessary losses.