Structure of check valves and globe valves
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Looking at the cross-sectional view, it seems that the straight-through globe valve has a structure similar to that of the horizontal lift check valve. Why then can’t a globe valve rely on self-sealing to prevent the flow of fluid? An external force also needs to be applied.
Check valves and globe valves share certain structural similarities, but their functions and principles are different. The main function of a check valve is to prevent the backflow of fluid. Its design includes a self-sealing valve disc that stops backflow, and components such as springs provide the necessary pressure to keep the valve closed at all times. The main function of a stop valve is to control or shut off the flow of the medium; its design requires an external force to be applied, either manually, electrically, or hydraulically, in order to open or close the valve. This is because globe valves have to withstand high fluid pressure and fluid momentum during use; if the flow of the medium is to be stopped relying only on the weight of the valve disc or other simple forces, it is easy for the valve to be forced open by the medium or to fail to achieve a complete seal. Therefore, to ensure the effectiveness and safety of check valves, it is necessary to take into account the operating environment and the properties of the medium during design and manufacturing, in order to select the appropriate valve structure and method of applying external force. .
The functions of the two types of valves are different: a globe valve prevents liquid from flowing in the forward direction, while a check valve prevents it from flowing in the reverse direction.
If a globe valve is the same as a check valve, then opening it requires back pressure.