What Is the Function of the Globe Valve?

The globe valve is used to cut off the flow of the medium. It is suitable for occasions that need to be opened frequently. Its sealing parts are the valve disc and the valve seat. In order to make the globe valve close tightly, the matching surface of the valve disc and the valve seat should be ground or a gasket should be used. The sealing surface can also be set with corrosion-resistant and wear-resistant materials such as bronze and stainless steel. The valve disc and the valve stem are connected flexibly, which facilitates the close matching of the valve disc and the valve stem. The lifting of the valve disc is generally controlled by the valve stem. The upper part is the hand wheel, and the middle part is the thread and the packing sealing section. The function of the packing is to prevent the medium in the valve body from leaking along the valve stem. So, what is the function of the globe valve?

The main function of the globe valve in the pipeline is to cut off or fill the fluid. This type of valve has a better ability to regulate flow than the gate valve, but it cannot regulate pressure and flow for a long time, otherwise, the sealing surface may be eroded by the medium and the sealing performance will be damaged. When the valve is closed, pressure needs to be applied to the valve disc to force the sealing surface to not leak. When the medium enters the valve from under the valve disc, the resistance that the operating force needs to overcome is the friction between the valve stem and the packing and the thrust generated by the medium pressure. The force to close the valve is greater than the force to open the valve, so the diameter of the valve stem should be larger, otherwise the top of the valve stem will be bent. From the appearance of the sealing valve, the medium flow of the globe valve enters the valve cavity from the top of the valve, and then under the action of the medium pressure, the force to close the valve is small, the force to open the valve is large, and the valve stem diameter can be reduced accordingly. At the same time, under the action of the medium, this type of valve is also more rigorous. When the globe valve is opened, the opening height of the valve disc is 25% to 30% of the nominal diameter. When the flow reaches a large value, the valve reaches the fully open position. Therefore, the fully open position of the globe valve should be determined according to the stroke of the valve disc.

The globe valve can be used for pipelines such as water, steam, and compressed air, but it is not suitable for pipelines with high viscosity, easy coking, and easy precipitation, so as not to damage the sealing surface. The valve disc moves vertically along the center line of the valve seat, relying on the rotation of the valve stem thread to make the valve disc sealing surface fit closely with the valve seat sealing surface, thereby cutting off the flow of the medium. The valve has a small overall working stroke, short opening and closing time, good sealing, small friction between the sealing surfaces, long service life, and can play a good adjustment performance.