Thread Content
It is used in the field of industrial automation process control for regulating process parameters such as medium flow rate, pressure, temperature, and liquid level. Based on the control signals in the automatic system, the opening degree of the control valve is adjusted automatically, thereby enabling regulation of the flow rate, pressure, temperature, and level of the medium. The selection of the valve body type is an important aspect in choosing a valve body. There are many types of valve bodies for control valves; the commonly used ones include single-seat, straight-seat, double-angle, diaphragm, low-flow, three-way, eccentric rotating, butterfly, sleeve, ball valve, and 10 other types. Before selecting a valve, it is necessary to conduct a thorough analysis of the medium, process conditions, and parameters of the control process, collect sufficient data to understand the system’s requirements for control valves, and determine the type of valve to be used based on this collected data. In making the specific selection, the following aspects can be considered: (1) The shape and structure of the valve core are primarily determined by factors such as the desired flow characteristics and unbalanced forces. (2) Corrosion resistance: Since the medium is corrosive, where possible, choose valves with a simple structure as long as their regulating function can be satisfied. (3) Wear resistance: When the fluid medium is a suspension containing high concentrations of abrasive particles, the interface between the valve core and the valve seat is subjected to severe friction each time it attempts to close. Therefore, the flow channel of the valve should be smooth, and the internal materials of the valve should be hard. (4) Prevent flashing and cavitation, which occur only in liquid media. In actual production processes, flash and cavitation phenomena not only affect the calculation of the flow coefficient but also cause vibrations and noise, thereby reducing the service life of the valve. Therefore, valves that prevent flashing and cavitation should be selected. (5) Temperature and pressure of the medium: When the temperature and pressure of the medium are high and subject to significant fluctuations, the materials for the valve core and valve seat should be selected based on the temperature and pressure conditions experienced by the small valve.