When choosing, we should mainly pay attention to the following aspects:
1, power supply type
2. Control type (switch type, regulating type)
3. Control signal and feedback signal of regulating valve
4. Size and type of valve body
5. Connection form
6. Use environment
Selection method of electric valve;
1. To determine the nominal pressure, it is not to remove PN with Pmax, but to find the corresponding PN from the table according to the three conditions of temperature, pressure and material and meet the PN value of the selected valve.
2. The leakage of the determined valve type meets the process requirements.
3. When determining the valve type, its working pressure difference should be less than the allowable pressure difference of the valve. If it is not less than that, another valve must be considered or selected from a special angle.
4. The medium temperature is within the working temperature range of the valve, and the ambient temperature meets the requirements.
5. Consider the anti-blocking problem of the valve according to the unclean medium.
6. Consider the corrosion resistance of the valve according to the chemical properties of the medium.
7, according to the pressure difference and hard medium, consider the erosion resistance of the valve.
8. Performance-price ratio considering comprehensive economic effects.
Electric valve selection steps:
1, the shape and structure of the spool are mainly considered according to the selected flow characteristics and unbalanced force.
2. Wear resistance When the fluid medium is a suspension containing high concentration of abrasive particles, the internal material of the valve should be hard.
3, corrosion resistance Because the medium is corrosive, try to choose a valve with simple structure.
4. Temperature and pressure of the medium When the temperature and pressure of the medium are high and change greatly, the valve whose valve core and seat material are less affected by temperature and pressure should be selected.
(5) Prevent flash evaporation and cavitation from occurring only in liquid medium. In the actual production process, flash evaporation and cavitation will form vibration and noise, shortening the service life of the valve. Therefore, flash evaporation and cavitation should be prevented when selecting valves.