Globe valves are mandatory sealed valves, so when the valve is closed, pressure must be applied to the disc to force the sealing surface not to leak. When medium by disc below into the valve 6, the operating force needed to overcome the resistance, is stem and packing of the friction force and the thrust produced by medium pressure, close the valve strength is stronger than open the valve, so it's bigger, the diameter of the stem or stem top bending failure happens. In recent years, from the seal valve, cut-off valve is replaced by the disc above the medium flow direction into the valve cavity, in the medium pressure at this moment, close the valve of the force is small, and the strength of the valve, the valve stem diameter can be reduced accordingly. At the same time, under the action of media, this kind of valve is also more rigorous. Our country valve "3 change give" once stipulated, stop valve direction, all adopt top - down.

When the globe valve is opened, the opening height of the disc is 25% ~ 30% of the nominal diameter, and the flow has reached the maximum, indicating that the valve has reached the fully open position. Therefore, the full open position of the globe valve should be determined by the stroke of the disc.