Globe valve

The closing of the stop valve is a plug valve, the sealing surface is flat or cone, and the disc moves in a straight line along the centerline of the seat. Stem movement form, (common name: dark rod), also has the lifting and rotating rod type, (common name: Ming bar) globe valve is the valve that is moving along the center line of the seat. According to this type of movement of the disc, the seat ventilation is proportional to the disc stroke. Due to open or close the valve stem travel relatively short, and very reliable cutting function, and due to the change of his seat and disc stroke proportional relationship, is very suitable for the traffic regulation. Therefore, this type of stop-stop valve is ideal for cutting or adjusting and throttling.

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 the medium from the disc below to the valve, the operating force to overcome resistance, is stem and packing friction with the thrust produced by medium pressure, close the valve force stronger than open the valve, so it's bigger, the diameter of the stem or stem top bending failure happens. There are three kinds of connection: flange connection, thread connection and welding connection. 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, the valve in this form is also tight under the action of the medium. China's valve "tri-chemical" has stipulated that the flow of the globe valve will be taken from the top down. The opening height of the disc shall be the opening height of the disc, and the maximum flow rate shall be 25% ~ 30% of the nominal diameter, indicating that the valve is fully open. Therefore, the full open position of the globe valve shall be determined by the stroke of the disc.