Valve resistance
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Can the flow resistance of a globe valve with the same specifications and model be dozens of times higher than that of a gate valve?
Difference in flow resistance between gate valves and stop valves of the same specifications and models: When a gate valve is fully open, the entire flow path is unobstructed, resulting in the lowest pressure loss for the fluid as it flows. Compared to stop valves, its main advantage lies in its lower flow resistance; the flow resistance coefficient of a typical gate valve is around 0.08–0.12, whereas that of a typical stop valve is around 3.5–4.5. The force required to turn it on and off is low. Gate valves are typically suitable for applications where frequent opening and closing are not required, and where the gate plate needs to remain fully open or fully closed; they are not appropriate for use in regulating flow or throttling. The stop valve exhibits high flow resistance throughout its entire stroke, along with significant unbalanced forces; as a result, the driving force or torque required is also much higher. However, it is well suited for regulating and throttling fluids. For media flowing at high speeds, when the gate is partially open, it can cause vibration in the valve; such vibration may damage the sealing surfaces of the gate and the valve seat. Throttling, in turn, exposes the gate to erosion by the fluid.
It’s very likely, because the purpose of a stop valve is to regulate flow, in other words, to “stop the flow”. The resistance is definitely quite high. Gate valves are mainly used for opening and closing – they are either fully closed or fully open (the gate plate of a valve that is in a semi-open position wears out very quickly), and the resistance of a valve that is fully open is very low.
It should be large; specifically, it depends on the manufacturer’s specifications. There are also stop valves with low resistance
I agree with what was said on the 2nd floor; therefore, the valve should be selected appropriately based on the specific operating conditions.
Valve manufacturers don’t provide the local resistance coefficient of valves – where can one find it?
It depends on the Cv value of the valve; typically, valve manufacturers have this parameter available.
What does the CV value mean? Please, brother, explain it to me
CV=1.17KV, KV: The maximum flow rate that the valve can handle at a pressure difference of one kilogram