Why are electric control valves so widely used?
Electric control valve is widely used in metallurgy, petrochemical industry and other fields, its stability, reliability also become more and more important.
According to the different medium, the valve body material of electric control valve also has a different choice, commonly used carbon steel, stainless steel 304 or 316, 316L and other materials, but also can choose fluorine lined control valve. There are several types of electric control valves: low-temperature control valves, high-temperature control valves, high-pressure control valves, small-flow control valves and so on.
Control valves are used to regulate the flow of operating variables, and are therefore called control valves. From the control system as a whole, a control system control is good or bad, are to achieve through the regulating valve, due to the following reasons, the regulating valve becomes very important.
Firstly, sanitary regulating valve is a throttling device, which is a moving part, compared with the detection element and transmitter, controller, in the control process, the regulating valve needs to constantly change the flow area of the throttle, so that the manipulation variable changes to adapt to changes in load or changes in operating conditions. Therefore, higher requirements are placed on the sealing, pressure resistance, and corrosion of the regulating valve assembly.
For example, the seal will make the regulating valve friction increases, the regulating valve dead zone increases, resulting in poor control system control quality, etc.
Secondly, the moving parts of the regulating valve is the main cause of running, bubbling, dripping, leakage, which not only causes waste of resources or materials, but also pollutes the environment and causes accidents.
The contact medium of the regulating valve material may be different from the contact medium of the detection element, so the regulating valve has higher requirements for corrosion resistance, strength, stiffness, etc.
Thirdly, the throttling of the regulating valve so that energy is consumed inside the valve, so reduce energy consumption, reduce the pressure loss of the regulating valve, and to ensure better control quality between the reasonable choice and balance.
Fourthly, the regulating valve throttling the fluid also causes noise, for example, when the regulating valve outlet pressure is lower than the liquid vapor pressure, resulting in flash; when the pressure downstream of the regulating valve is higher than the liquid vapor pressure, resulting in cavitation. The noise caused by the regulating valve and the design of the regulating valve flow path, operating pressure, the characteristics of the controlled medium, etc. Therefore, reduce noise, reduce pressure loss and other regulating valve to put forward higher requirements.
Fifthly, the adaptability of the regulating valve. It is installed in a variety of different production processes, the production process of high temperature, low temperature, high pressure, high flow, micro flow and other operating conditions require a variety of different functions of the regulating valve, the regulating valve can adapt to the requirements of different applications.
Sixthly, detection elements and transmitters, controllers and other developments are fast, and more manpower and material resources are invested. Relatively speaking, it is usually considered that the regulating valve structure is simple to adjust, the importance of the regulating valve is reflected therefore the regulating valve invested in the research and development of human and material resources is relatively insufficient.
How to Maintain Electric Control Valve?
Electric control valve installation and use to pay attention to the following aspects:
(1) electric control valve is classified as a field appearance, requiring the ambient temperature should be -25 ~ 60 ℃ scale, relative humidity ≤ 95%. Is the installation of open air or high temperature occasions, should adopt waterproof, cooling methods. There is a source of vibration party to stay away from the source of vibration or add anti-vibration methods.
(2) regulating valve should generally be installed straight, in special cases can be skewed, such as skewed point of view is very large valve own weight is too large for the valve should add support pieces to protect.
(3) electric regulating valve installation should be cleaned before the pipeline, to exclude dirt and welding slag. After installation, in order to ensure that no impurities remain in the valve, the valve should also be cleaned again, that is, when passing into the medium should make all valves open to avoid impurities stuck. After using the handwheel organization, should be rehabilitated to the original neutral position.