1、 Working principle of flange type high-pressure shut-off valve

High pressure shut-off valves belong to the forced sealing type, so when the valve is closed, pressure must be applied to the valve disc to force the sealing surface not to leak. When the medium enters the valve from below the valve disc, the resistance that needs to be overcome by the operating force is the friction force between the valve stem and packing and the thrust generated by the pressure of the medium. The force to close the valve is greater than the force to open the valve, so the diameter of the valve stem needs to be larger, otherwise it will cause the valve stem to bend. In recent years, with the emergence of self sealing valves, the medium flow direction of globe valves has changed from above the valve disc to enter the valve chamber. At this time, under the pressure of the medium, the force to close the valve is small, while the force to open the valve is large, and the diameter of the valve stem can be correspondingly reduced. At the same time, under the action of the medium, this type of valve is also relatively tight. The "three modernizations" of valves in China once stipulated that the flow direction of shut-off valves should be from top to bottom.


2、 Structural Characteristics of Flange High Pressure Stop Valve
1. Carefully selected materials, in compliance with relevant domestic and international standards, with a reasonable structure and beautiful appearance.

2. The sealing surfaces of the valve disc and valve seat are made of iron based alloy overlay welding or Stellite cobalt based hard alloy overlay welding, with good wear resistance, high temperature resistance, corrosion resistance, scratch resistance, and long service life.

3. The valve stem has undergone quenching and surface nitriding treatment, which has good corrosion resistance and scratch resistance.

4. Various piping flange standards and flange sealing surface types can be used to meet various engineering needs and user requirements.

5. The valve body material variety is complete, and the packing and gasket can be reasonably selected according to actual working conditions or user requirements, which can be suitable for various pressure, temperature, and medium working conditions.

6. The reverse seal is made by connecting the sealing seat with threads or welding austenitic stainless steel on the body, which is reliable in sealing. Replacing the filler can be done without stopping the machine, making it convenient and fast without affecting the system operation.