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中文简体Knife gate valve and globe valve are two commonly used shut-off valves. The main differences between them are as follows:
First, the structure is different:
Knife gate valve is more complex in structure than globe valve, and its height dimension is larger. From the perspective of appearance, knife gate valve is shorter and taller than globe valve. In particular, the rising stem knife gate valve requires a higher height space, which is required when the installation space is limited. Note.
Second, the sealing surface is different:
When the knife gate valve is opened and closed, the valve core and the valve seat sealing surface are always in contact and friction with each other, so the sealing surface is easy to wear, especially when the valve is close to the closed state, the pressure difference between the front and rear of the valve core is large, and the sealing surface wears more. Serious; once the valve disc of the globe valve is in the open state, there will be no contact between its valve seat and the sealing surface of the valve disc, so the mechanical wear of its sealing surface is small, but if the medium contains solid particles, it is easy to damage the seal noodle. The sealing surface of the knife gate valve has a certain self-sealing ability, and its valve core is tightly contacted with the sealing surface of the valve seat by the medium pressure to achieve tightness and no leakage.
Three, the flow resistance is different:
When the knife gate valve is fully open, the entire flow channel is straight, and the pressure loss of the medium at this time is the smallest. Compared with the globe valve, its main advantage is that the fluid flow resistance is small. The flow resistance coefficient of ordinary knife gate valves is about 0.08~0.12, The resistance coefficient of ordinary globe valve is about 3.5~4.5. Small opening and closing force. Knife gate valves are usually suitable for working conditions that do not need to be opened and closed frequently, and keep the gate fully open or fully closed, and are not suitable for adjustment and throttling. The flow resistance of the globe valve in the entire stroke is large, the unbalanced force is large, and the required driving force or torque is correspondingly much larger.
