Selection of control valve type

It is used for the adjustment of process parameters such as medium flow, pressure, temperature and liquid level in the field of industrial automation process control. According to the control signal in the automatic system, the opening of the valve is automatically adjusted to realize the adjustment of the medium flow, pressure, temperature and liquid level. The choice of valve body type is an important part of the valve body selection.
There are many types of regulating valve body, commonly used are single valve seat, straight valve seat, double angle, diaphragm, small flow, three-way, eccentric rotation, butterfly valve, sleeve, ball valve, etc. 10 types.
Before selecting a valve, carefully analyze the medium, process conditions and parameters of the control process, collect enough data, understand the system's requirements for the regulating valve, and determine the type of valve to be used based on the collected data.
In the specific selection, the following aspects can be considered:
(1) The shape and structure of the valve core are mainly considered according to the selected flow characteristics and unbalanced force.
(2) Corrosion resistance Due to the corrosive nature of the medium, a valve with a simple structure should be selected as far as possible when the adjustment function can be met.
(3) Wear resistance When the fluid medium is a suspension containing a high concentration of wear particles, the valve core and valve seat interface will be severely rubbed and closed every time. Therefore, the flow channel of the valve should be smooth, and the internal material of the valve should be hard.
(4) Prevent flash and cavitation, flash and cavitation are only produced in liquid medium. In the actual production process, flashing speed and cavitation not only affect the calculation of the flow coefficient, but also cause vibration and noise, which shorten the service life of the valve. Therefore, valves that prevent flashing and cavitation should be selected.
(5) The temperature and pressure of the medium. When the temperature and pressure of the medium change greatly, the valve core and seat material should be selected according to the temperature and pressure of the small valve.