Reasons why valves with small diameters are easy to open
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Why is it easier to open the valve when the diameter is smaller under a high pressure difference?
This post was last edited by Wenwu6963 on 2016-1-21 at 08:53. The friction acting on the valve stem screw is related to the force acting on the valve core; the force on the valve core is proportional to the back pressure and its own area. Therefore, for the same valve, the higher the back pressure, the harder it is to open. By the same logic, with the same back pressure, the larger the area of the valve core, the harder it is to open. Conversely, the smaller the diameter, the smaller the area of the valve core, so valves with smaller diameters are easier to open.
The higher the backpressure, the better it should be to operate, right?
The resistance at the sealing surfaces, contact surfaces, and connection surfaces is low, right?
First, consider whether the valve you are using is of the flow-open type or the flow-close type; those of the flow-open type are certainly easier to open. Flow-close valves are more difficult to operate under high pressure differences compared to those of the flow-open type. Additionally, pressure is defined as the force per unit area, so it is likely that the pressure will be lower if the area subjected to the force is small. The above are merely my personal opinions; please correct me if I’m wrong: lol
It’s not the case that turning it in the direction of the switch makes it easier to operate; rather, this leads to increased resistance in the valve stem, which is why it’s difficult to operate either way
No, the greater the pressure, the greater the friction between the valve stem and the packing
If the pipe diameter is small, the pressure acting on the valve will be low. The contact area is small.