Classification and working principle of mechanical steam trap The steam trap identifies steam and condensate based on three principles: density difference, temperature difference and phase change. So according to these three principles, three types of trap valves are manufactured: mechanical type, thermal static type and thermal dynamic type. 1、 Mechanical drain valve: mechanical drain valve, also known as float valve, uses the density difference between condensate and steam to make the float lift and drive the valve disc to open or close through the change of condensate level, so as to achieve the purpose of steam blocking and drainage. The mechanical drain valve has a small degree of supercooling and is not affected by the changes of working pressure and temperature. When there is water, it is discharged immediately. There is no water in the heating equipment, which can make the heating equipment achieve the best heat exchange efficiency. The maximum back pressure rate is 80%, and the working quality is high. It is the most ideal drain valve for production process heating equipment.

1、 Functional requirements of electric control valve. According to the requirements of engineering control, for electric control valve, the control function is completed by electric device. The application of electric control valve is accomplished by the linkage of opening, closing and regulation of the valve, rather than manual electrical control or computer control. At present, the application of electric devices is not just to save manpower. Because the products of different manufacturers are different in function and quality, it is very important for the project to select electric devices and valves.